Signs point to North Korea nuclear test

North Korean leader Kim Jong Un guides a flight training of KPA Air and Anti-Air Force Unit 188 in this undated photo released by North Korea's Korean Central News Agency. REUTERS/KCNA

The United States said today it was monitoring the Korean
peninsula closely after reports that North Korea may be
planning another nuclear test and it urged Pyongyang not to
take any step that would threaten regional peace.

South Korean news reports quoted the South Korean government
as saying that heightened activity had been detected at North
Korea's underground nuclear test site, indicating possible
preparations for another atomic test.

The reports come just before US President Barack Obama is due
in Japan and South Korea, where he will discuss ways to deal
with North Korea's nuclear weapons programme. Obama is due in
Tokyo on Wednesday and in Seoul on Friday.

"We continue to urge North Korea to refrain from actions that
threaten regional peace and security and to comply with its
international obligations and commitments," she told a
regular news briefing.

South Korea's Yonhap news agency quoted South Korean Defense
Ministry spokesman Kim Min-seok as saying that "a lot of
activity" was being seen at the Punggye-ri test site.

"So our forces are keeping in mind the possibility that North
Korea may suddenly conduct a nuclear test in a short period
of time, or as in previous cases, deceive us with what
appears to be a nuclear test."

North Korea warned last month it would not rule out a "a new
form" of nuclear test after the United Nations Security
Council condemned Pyongyang for launching ballistic missiles
into the sea.

Recent commercial satellite imagery indicates North Korea has
begun new operations at Punggye-ri, said 38 North, a North
Korea monitoring website run by Johns Hopkins University's
School of Advanced International Studies in Washington.

But it said there was little evidence to suggest a test would
take place during Obama's visit to Seoul. This "may be
possible but appears unlikely," it said.

Increased activity had been seen in a six-week period from
early March to April 19, including in an area where there
were two completed tunnels, 38 North said.

"In particular, there appears to be movement of crates, boxes
and materials near the entrances, possibly into the tunnels,"
it said.

However it added: "Recent operations at Punggye-ri have not
reached the high level of intensity - in terms of vehicle,
personnel and equipment movement - that occurred in the weeks
prior to past detonations."

The activity "could represent an early stage of preparations
for a test or may be intended for a less provocative purpose,
such as conducting maintenance after a long winter" 38 North
concluded.

When asked what Pyongyang meant by a "new form" of nuclear
test, North Korea's deputy ambassador to the United Nations
said on April 4 the world would have to "wait and see."

Nuclear expert Jeffrey Lewis, of the Monterey Institute of
International Studies in the United States, said this month
that the reference to a new form of test could mean
simultaneous detonation of two or more devices as part of a
program of more intense nuclear testing expected over the
next few years.

While North Korea has detonated several nuclear devices Since
2006, analysts have expressed doubt it yet has the technical
capability to reliably mount a nuclear warhead on a missile.

Diplomats have said it is possible the U.N. Security Council
will respond to last month's North Korean missile tests by
expanding a sanctions blacklist to include more North Korean
entities involved in Pyongyang's missile program. But they
said it could take weeks to reach agreement.

The council expanded its sanctions on North Korea after its
third nuclear test in February 2013.

The United States said it held "productive" talks with China
on North Korea last week, part of stepped up international
diplomacy after Pyongyang's nuclear test warning.

China, North Korea's main ally, has warned against any action
that could lead to the escalation of tensions.